Physiological Responses of Wheat Phosphorus-Efficient and -Inefficient Genotypes in Field and Effects of Mixing Other Nutrients on Mobilization of Insoluble Phosphates in Hydroponics
2007
Liu, G.D. | Dunlop, J. | Phung, T. | Li, Y.C.
To elucidate the mechanism of mobilization of insoluble phosphates, a field trial and a split root experiment in a growth chamber were conducted. The results showed that a phosphorus (P)-efficient wheat genotype, Yanzhong 144 (YZ), transpired 50% less than a P-inefficient genotype, 80-55. At the grain-filling stage, the free water content in YZ's rhizosphere was 2.4 times of that of 80-55's. When either tricalcium phosphate Ca3(PO4)2 or ferric phosphate (FePO4) were combined with the other nutrients in the same solution, total dry-matter production was 140% greater for Ca3(PO4)2 and 60% greater for FePO4 than when these P sources were each supplied alone to one half of the root system while the other nutrients were supplied to the other half. The excess absorption of cations over anions by the roots facilitated mobilization of insoluble phosphates. The P-efficient genotype was also water efficient, and the insoluble phosphates TCP and FP were phyto-available in water culture.
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